Porous materials, such as cellulosic materials, need to be protected from mold growth, insect attack, rot and water impregnation to help preserve the physical properties of the cellulosic material. One example of such a cellulosic material is wood. A variety of treatment agents and preservation methods are known to preserve cellulosic materials.
Modern preservation methods typically involve pressure treating the cellulosic material with a treating agent. Pressure treatment typically allows the treating agent to penetrate throughout the porous structure of the cellulosic material. The treating agent is typically a chemical compound selected to impart the desired physical properties to the cellulosic material. For example, treating agents that increase hardness, add water resistance and improve the dimensional stability of the cellulosic material are of interest. Wood is capable of absorbing as much as 100% of its weight in water which causes the wood to swell, which after loss of water through evaporation causes the wood to shrink. This process of water absorption/evaporation is non-uniform and creates internal stresses in the wood leading to splitting, warping, bowing, crooking, twisting, cupping, etc. Also, water can serve as a pathway for organisms that degrade the cellulosic material, such as insects or fungus. Treating agents that repel insects, or minimize the formation of fungi/molds, or improve the overall durability of the cellulosic material are of interest. Further, treating agents can improve wind resistance, ultraviolet radiation resistance, stability at high and low temperatures, pest resistance, mold resistance, fire resistance and other issues which might affect the physical properties of the cellulosic material.
Termites are one of the most significant insect groups responsible for wood damage. In order to mitigate termite damage, the use of naturally durable wood species, preservative treatments, and engineered wood products have been employed. However, the need for improved technologies for termite resistance are desirable due to the limited availability of durable woods, the high percentage weight gains required for preservatives to provide efficacy, and the “unnatural” look of engineered wood. A technology which is provides termite resistance and dimensional stability to wood is highly desirable.
One compound used to treat wood is quaternary ammonium compounds, referred to herein as quats. Quats are known to add insect and fungi resistance to wood. Quats are also known to dissociate from wood, and can be a skin and respiratory irritant and cause harm to aquatic systems. Another disadvantage to quats is they can behave as surfactants and make wood exposed to rain pick up moisture more easily.
An improved treating agent for cellulosic materials is desired. In particular, a treating agent which prevents dissociation of quats from the cellulosic material while still maintaining good insect and fungi resistance is desired. Additionally, improved dimensional stability when using quats is desired.